1. Field of Invention
The present invention relates to a tube adapter for a shell-type centrifuge rotor.
2. Description of Prior Art
So-called shell-type rotors are well-known in centrifuge art. U.S. Pat. No. 5,362,300 (Christensen), assigned to the assignee of the present invention, is an example of such a rotor construction.
In the typical instance a shell-type rotor includes a generally planar body member onto which an upper plate is attached. The upper plate has an array of cavities each sized to accept a sample container therein. A shell-type rotor has the capacity to hold a relatively large number of sample containers. In a typical instance a rotor may have on the order of twenty-four cavities. Owing to its relatively low cost of manufacture a shell-type rotor is a popular rotor choice when a clinician is presented with the task of spinning a large number of relatively small sized samples (each on the order of two milliliters).
When received in a cavity in the plate each container projects into an open space defined between the between the upper surface of the body member and the undersurface of the plate. The sample container receives no support other than that given by the top surface of the plate. Such a level of support is usually sufficient when the rotor is used for protocols that remain in the low speed regime (i.e., less than eleven thousand rpm.)
However, a shell-type rotor may also be used for protocols that extend into the superspeed regime, where rotational speeds on the order of fifteen thousand rpm are not unusual. When used at a speed in the superspeed regime it may be necessary to provide some form of support for the sample container. In the rotor disclosed in U.S. Pat. No. 4,832,679 (Bader) an adapter, or sleeve, is inserted into the cavities in the plate to provide support for sample containers.
Since a tight fit is required between a support sleeve and a sample container in order for the sleeve to provide the necessary support to the container the sleeve may tend to be extracted from the rotor when the tube is removed from the cavity. Due to the high volume (in terms of number) of sample containers that a clinician processes it is considered an inconvenience for the clinician to have to handle the support sleeves in addition to the sample containers in the event the sleeve becomes removed from the rotor with the extraction of the container.
It is therefore believed advantageous to provide a shell-type centrifuge rotor having a container support sleeve wherein the support sleeve is axially fixed with respect to the rotor so that the sleeve remains with the rotor when the sample container which it is supporting is removed from the rotor.